1. Field of the Invention
This invention relates to a spread illuminating apparatus for use as an illuminating means in a signboard or various kinds of reflection type display apparatus, in particular, a liquid crystal display apparatus.
2. Related Art
A liquid crystal display apparatus is operated at a low electric consumption and characterized by its low profile and light weight, so its demand as a display apparatus mainly for computer has been increased. However, a liquid crystal as a constituent element of a liquid crystal display apparatus does not emit light by itself, and therefore needs an illuminating means to view a picture as opposed to a light emitting type element such as a picture tube. In particular, in a recent demand for a lower profile, a thin plate-like spread illuminating apparatus of side light type (light conductive member type) has been often used as an illuminating means for lighting a liquid crystal display apparatus.
One example of such side light type spread illuminating apparatus is shown in FIGS. 9 to 12.
In FIGS. 9 to 11, this spread illuminating apparatus 1 is formed in general with a transparent substrate 2 made of a transparent material and a longitudinal light source 4 disposed close to one side end face 3 of the transparent substrate 2. A liquid crystal panel 5 is disposed under the transparent substrate 2 and this spread illuminating apparatus 1 functions as an auxiliary illuminating device for the liquid crystal panel 5.
And, a box-like metal frame 6 is provided so as to enclose the spread illuminating apparatus and the liquid crystal panel 5.
The transparent substrate 2 is configured so-called wedge-like in section, in which the thickness becomes smaller as it gets away from the one side end 3.
The light source 4 is formed in general with a light conductive member 7 made from a longitudinally triangular plate of a transparent material and disposed close to and along the one side end face 3 of the transparent substrate 2 and a spot-like light source 8 disposed opposite to one end 7a of the light conductive member 7 and mounted on a flexible printed circuit board 9 (hereinafter referred to as xe2x80x9cFPCxe2x80x9d).
Further, a surface 7c (second surface of the light conductive member) opposite to a surface 7b (first face of the light conductive member) facing the transparent substrate 2 is formed oblique relative to the first surface 7b of the light conductive member in a plan view. An optical path conversion means 10 which is formed with grooves 10a approximately triangular in section and plane portions 10b located between the grooves 10a is provided on the second surface 7c of the light conductive member. And, although the spot-like light source 8 is disposed at the one end 7a, light which enters the one end 7a of the light conductive member 7 is emitted uniformly from the first surface 7b of the light conductive member.
A light reflection pattern 12 is formed on one surface 11 (upper side in FIG. 11, hereinafter referred to as xe2x80x9cupper facexe2x80x9d) of the transparent substrate 2, whereby the brightness is adapted to become approximately uniform at every portion of the transparent substrate 2 independent of the distance from the light conductive member 7.
The spot-like light source 8 is disposed on the FPC 9, and terminals 14 are connected to copper foils (conductive portion) 15. Portions lattice-hatched in FIG. 10 denote solder fillets 16.
In the prior art shown in FIGS. 9 to 11, the terminals 14, the solder fillets 16 and so on are disposed close to the metal frame 6, therefore a shortcircuit is apt to happen.
And, while it is demanded that light from the spot-like light source 8 enter the light conductive member 7 efficiently, in the above prior art, since the spot-like light source 8 is almost exposed, light L leaks outward from the circumference of the spot-like light source 8 as shown in FIG. 12, therefore the above demand has not been satisfied.
Further, the FPC 9 is required to be positioned suitably and not to come off at the time of assembling.
The present invention has been made in the light of the above problem and requirements and an object thereof is to provide a spread illuminating apparatus, in which a shortcircuit can be prevented and light emitted from the spot-like light source can be used efficiently.
Another object of the present invention is to provide a spread illuminating apparatus, in which the FPC can be properly positioned and prevented from coming off.
According to a first aspect of the present invention, in a spread illuminating apparatus in which a rectangular light source is disposed close to a side end face of a transparent substrate made of a transparent material, the light source is formed with a bar-like light conductive member made of a transparent material and disposed along and close to at least one side end face of the transparent substrate and a spot-like light source disposed on at least one of both ends of the light conductive member and mounted on an FPC, wherein the FPC comprises a substrate on which the spot-like light source is mounted and a cover which extends from the substrate, covers the spot-like source and terminals disposed close to the spot-like light source and insulates electrically them from the surrounding.
According to a second aspect of the present invention, in the first aspect, the cover is formed with a bent extension from the substrate.
According to a third aspect of the present invention, in the first or second aspect, the cover comprises bend portions.
According to a fourth aspect of the present invention, in the second or third aspect, the cover comprises a reinforcing film on its inner surface clear of the bend portions.
According to a fifth aspect of the present invention, in the fourth aspect, the reinforcing film is formed of a material with a high thermal conductivity such as copper foil.
According to a sixth aspect of the present invention, in the fourth aspect, the reinforcing film has a low transparency.
According to a seventh aspect of the present invention, in any one of the second to sixth aspects, a cover coating is removed at the bend portions.
According to an eighth aspect of the present invention, in any one of the first to seventh aspects, a frame is provided which covers the light source and extends passing the one side end of the transparent substrate to overhang and fix the transparent substrate, a spot-like light source housing portion is provided at the end of the frame to house a spot-like light source disposing portion to dispose the spot-like light source in the FPC, and a positioning mechanism for determining the position of the FPC is provided at the spot-like light source disposing portion.
According to a ninth aspect of the present invention, in any one of the first to seventh aspects, a frame is provided which covers the light source and extends passing the one side end of the transparent substrate to fix the transparent substrate, a spot-like light source housing portion is provided at the end of the frame to house the spot-like light disposing portion to dispose the spot-like light source in the FPC, and a mechanism for preventing the FPC from coming off from the spot-like light source housing portion is provided at the spot-like light source disposing portion.
According to a tenth aspect of the present invention, in any one of the first to seventh aspects, a frame is provided which covers the light source and extends passing the one side end of the transparent substrate to fix the transparent substrate, a spot-like light source housing portion is provided at the end of the frame to house the spot-like light disposing portion to dispose the spot-like light source in the FPC, and an integrated mechanism for positioning the FPC and at the same time preventing the FPC from coming off from the spot-like light source housing portion is provided at the spot-like light source disposing portion.